Do CAC Green Stickers Add Value?

Anyone who has followed coin collecting closely
no doubt has encountered the "Green Sticker", slang for a CAC label
attached to a slabbed coin.

Let's decipher this lingo. When mentioning CAC Green Stickers, a
slabbed coin pertains to a coin graded and encapsulated by the PCGS or
NGC grading services. CAC stands for Certified Acceptance Corporation,
an organization founded in 2007.

The CAC closely studies a slabbed coin and renders an opinion if the
coin is correctly graded, overgraded, or undergraded. If CAC verifies
the coin meets the standard for strict quality for its grade, it earns
a CAC green, tamper-evident holographic sticker, affixed to the slab.
It is a signal the coin is "solid" for its grade.

Coins that are judged to be borderline for its grade or overgraded get
no sticker at all. Those that are undergraded get a gold CAC label --
but we'll save that topic for another time.

Hundreds
of thousands of coins have been submitted to CAC over the
years. The incentive for collectors is the hope their coin will appear
"solid for the grade" in the eye of the CAC evaluator and will earn a
Green Sticker. Since the Green Sticker has become a telltale sign for
quality on the marketplace, it is more likely to sell for a better
price when compared to an otherwise virtually identical coin (i.e. same
coin type, grade, grade service, etc.), at least so goes the theory.

Does anyone really know how much more a CAC coin is likely to bring
versus its non-CAC counterpart? Has there ever been any data gathered
to validate the claim that CAC coins are worth more? The answer is yes,
there has been. In fact, if you write to the CAC, they'll send you a
PDF of a study they did several years ago to bolster this claim.

Trust but verify. These are words that have resonated with me since the
1980's. Thankfully, several of the large auction houses have searchable
databases available online of many thousands of coin sales. I tapped
into some of this data to do a small scale research project of my own.
My goals were to estimate: (A) how often CAC coins sell for more than
their non-CAC counterparts, and (B) the average percentage premium
generated by the CAC green sticker.

Before posting the results, let's cover the methodology:

Step 1: For a given recent sale, pulled
out all the CAC coins. In a
sale of a three thousand coin lots, typically a few hundred of them
carry
the CAC green sticker.

Step 2: For the CAC coins, pull out matching coins from
remainder of
the sold coins from the sale. Definition of a match: same coin type,
date,
denomination, variety, grade, and grading service.

Step 3: If one of the coins in a matched pair had some
other degree of separation, such
as color (if applicable -- for example, Red or Red-Brown), a "Plus",
"Secure" or some other type of additional quality indicator, or
anything else, it was removed from the study. The objective of Steps 2
and 3 was to get the best "apples to apples" comparison possible.

Step 4: Go to another set of auction sale results and
repeat
Steps 1 through 3.
Please note this methodology only isolated matches within the same
sale. In other words, both coins in a matched pair were sold at
essentially the same time. One could argue it would've been acceptable
to match pairs sold a few months apart, but there was no trouble
gathering data points for the study with this approach. Thus, all
matched pairs were sold literally within hours of one another. Four
sets of auction results were analyzed, covering 10,000 lot sales, from
which 90 fully matched pairs were distilled.

Step 6: Discard outliers. There were only two outliers,
one the high
side and one on the low side, leaving 88 pairs in the study.

Step 7: Create a chart to represent results of the study
and perform
other statistical analyses.

Forgive me for boring you to death, but it
really is necessary to reveal the methodology underlying the study. The
chart below captures
the results:

The key points gleaned from the chart above are:

Bottom Line: Yes, the vaunted CAC Green Sticker
DOES INDEED tend to
improve the selling price of a given coin when compared to its non-CAC
counterpart. On average, this premium is about 25%, but this should
never be viewed as an absolute rule. Your CAC coin may or it may not
sell at a premium, but the odds are good that it will, although the
size of the premium (if any at all) could be small or very large.